A four-time Emmy winner for playing his most popular part to date (with an additional Emmy for his recurring Sideshow Bob voice role on "The Simpsons"), the actor launches a huge and highly effective image change as the powerful and troubled mayor of Chicago when the Starz drama series "Boss" debuts Friday, Oct. 21.

Tom Kane rules the Windy City in his own imperious way, and if he has faced challenges before, he gets his greatest one in the show's opening scene. His neurologist (Karen Aldridge) informs him of his progressive brain disorder, prompting his worry that he'll soon lose everything personally as well as professionally.

Not that his personal life isn't already frayed: He's estranged from both his wife and daughter (Connie Nielsen, Hannah Ware). At the office, Kane relies on his chief of staff (Martin Donovan); his aide ("Beverly Hills, 90210" alum Kathleen Robertson) and the ambitious state treasurer (Jeff Hephner) are among others he deals with often.

Along with filmmaker Gus Van Sant ("Good Will Hunting"), who directed the premiere, Grammer is an executive producer of "Boss." So is series creator Farhad Safinia, with whom Grammer says he began working "sometime after my marriage at the time (to 'Real Housewives of Beverly Hills' co-star Camille Grammer) was falling apart. This character's life was falling apart, and it was meant to be derivative of some Shakespearean stuff.

"Basically, he's Lear," Grammer says. "That being said, we don't want to pigeonhole it so that people say, 'Oh, they're trying to make a "King Lear" story.' It's a tragedy about a man who is not necessarily a tragic figure at first but will become that as he learns to love. That's my idea of where this character is going."

Despite Kane's power in holding a city's top office -- evidenced early in "Boss" when he literally brings an associate to his knees -- Grammer maintains the show is "not really meant to be about politics. It is political in nature, and Chicago lends itself to the idea of a kingdom, a place where one man can make a difference. That's what we're borrowing from Chicago, that these men who have existed throughout its history are compelling, great characters."

And Grammer clearly is pleased to be adding such a character to the roster. He defines Kane as "a genius at understanding how to push or manipulate somebody. I don't even know that it's always conscious what his skill is, and the malady he is dealing with suddenly challenges his trust of himself. That's what makes him such an interesting guy to play."

Indeed, Kane fears exposure of his medical condition, evident in his eyes when his uncontrollably shaking wrist knocks loudly against the bottom of a desk during a well-attended hearing. Grammer says Kane's illness "doesn't have an identity in our society. Maybe by virtue of this, it will be given one, but it's still relatively undiscovered in terms of its symptoms and its course. We just happened upon it, and it gives us license for what we need to tell the story."

That need is described by Grammer as the desire "to put a clock on this guy's life. We wanted to give ourselves something that said, 'You have to make some decisions,' so that there's a engine that drives this thing other than politics."

Without a doubt, though, politics is a huge aspect of "Boss." It doesn't take a particularly kind view of those in that field, and Grammer is OK with that. He reasons that the show tries to "find the flaw in each character, and it's really exciting stuff. I have to tell you, the storytelling in this particular show is some of the most fun (material) I've ever done in my life. These characters all find their own ways to destroy themselves."

Even so, Grammer defends Kane as "still principled and willing to do anything to accomplish what he thinks is best. He's not immoral, he's amoral. He comes from a very utilitarian frame of mind that says, 'This is what will help this city continue to run and be this magical place.' He wants it to stay that way, and he wants his own image to be reflected in that."

One of Grammer's aims in doing "Boss" is to bust through his "Frasier" image, fond of it -- and grateful for it -- as he is. "It was time to just do something completely different. No one was comfortable with me playing a different kind of guy who was funny. They weren't willing to see that guy, even in (Fox's TV news sitcom) 'Back to You,' which was arguably a pretty good show.

"Frasier is a lovable, affable, memorable character, but he made it almost impossible for someone to be able to watch you unless you did something as dramatically different as this."

A home-screen staple ever since Frasier made his first "Cheers" appearance in 1984. Grammer realized it likely would take going to the cable realm for his latest television opportunity. Starz likes what it's seen so far: Even before it premieres, "Boss" has been renewed for a second season.

"Everybody finds their niche and wants to stay there, and they want to keep actors there as well," Grammer reflects. "They don't like the idea that an actor can do something completely different, because that doesn't serve any business model.

"It's all about the bottom line in television, and I don't resist that, but you should be able to function creatively and do something extraordinary. I've been given this chance, within the context of cable television, to be able to play something I wouldn't be able to on (broadcast) network television."